Alex Salmond’s Scottish independence campaign needs to win over almost
three-quarters of undecided voters if it is to emerge victorious from next
year’s referendum, according to a detailed analysis.

Ipsos MORI said its polling suggested the First Minister would have a better chance if he watered down his strategy of telling voters independence is a small step and adopt a more radical agenda.

In a bid to reassure voters, Mr Salmond has claimed that everything from the currency to Scotland’s EU status would remain the same in the face of expert warnings otherwise.

But Mark Diffley, the pollster’s research director, said undecided Scots from poorer backgrounds would be more like to vote yes if he was more frank in promising drastic change.

With the Scottish Government’s prospectus on independence being published in the autumn, he also warned that the nationalists will have to start producing more “substantial” answers about independence if they are to win.

The detailed findings emerged after Nate Silver, one of the US’s most eminent polling experts, said the nationalists have “virtually no chance of winning”.

His intervention came as Gordon Wilson, Mr Salmond’s predecessor as SNP leader, called the separatists’ campaign “sterile” and urged them to make a concerted attack on the English “southern cancer”.

Mr Diffley disagreed with Mr Silver that the referendum was basically a “done deal” but said Ipsos MORI’s analysis showed the cards were stacked against a nationalist victory.

So far, 56 per cent of Scots say they are both certain to vote and are absolutely certain about how they will cast their votes. Of this group, two-thirds want to remain part of the UK and 33 per cent support independence.

Although this means that 44 per cent are either not sure whether or how they will vote, Mr Diffley said there is nothing to suggest that their attitudes are markedly different from those who are.

“As it looks now, the yes side would need to capture somewhere between two-thirds and three-quarters of that group in order to win next year,” he said, estimating that around 70 per cent would have to vote Yes.

But he said voters are currently reluctant to vote for independence because they have too little information about the implications for their savings, mortgage, jobs and the NHS.

"I don't think a lot of the undecideds will be persuaded to vote yes unless they get some pretty substantial answers to these questions,” he said.

The analysis found that 25 per cent of Scots might not vote at all in the referendum, eight per cent will vote but are undecided, and 11 per cent will cast their ballots but may change their minds before the September 2014 referendum.

Although this could offer a glimmer of hope for Mr Salmond, Ipsos MORI said that supporters of Yes Scotland and the SNP were more likely to change their minds about independence than Unionists.

More than one in five SNP voters (22 per cent) said they may drop their support for separation, with a further 14 per cent saying they were still undecided. Twenty per cent of Yes Scotland supporters said they may perform an about-turn and back the Union.

The pollsters also found that Scots living in poorer communities are more likely to back independence but they are also less sure about whether they are actually going to vote.

“The likelihood is that these people are less frightened of taking a risk, they are more prepared for significant change – maybe they don't have a job, they don't have a mortgage, they don't have lots of savings,” Mr Diffley said.

“So, our conclusion from that might be that perhaps the (separatist) offering could be more radical, because you could pick up more people in those areas."

Mr Salmond has attempted to increase support for separation by claiming that Scotland would retain unions of currency, monarchy, society and defence with the remainder of the UK.

But academics and UK minsters have undermined this claim and Mr Wilson yesterday delivered a scathing assessment of the Yes campaign, saying it is being presented with “all the excitement of a robot”.

A Yes Scotland spokesman said the Ipsos MORI analysis showed there was “everything to play for”, adding: “We know from various polls, as well as our own research, that large numbers of voters have yet to decide but the more people learn about independence the more likely they are to vote yes.”